Electric vs Mixer Shower: Which Should You Choose?

Updated July 2026 · Emergency Plumber Chelsea

How an electric shower works. Cold water from the mains goes into the unit on the wall, passes over an electric heating element and comes out of the head at the temperature you set. Because it heats water on demand, it never runs out of hot water and does not need the boiler at all. The limit is power: the element can only heat so much water per minute, so the flow is gentler than most mixers, and in winter, when the incoming mains is colder, you may need to turn the flow down to keep the temperature up. Higher kilowatt ratings give a better shower but draw more current.

How a mixer shower works. A mixer valve takes hot and cold from your existing plumbing and blends them to a set temperature. A thermostatic mixer holds that temperature steady even if someone runs a tap elsewhere, and is the safer choice in family homes. How good the shower feels depends on what feeds the valve: a combi, an unvented cylinder, a gravity-fed cylinder with a pump, or a gravity supply on its own. The valve can be a bar mixer on the wall surface or concealed behind the tiles with only the controls showing.

What your heating system can supply. This is the question that settles most decisions. With a combi boiler, a mixer shower gets mains-pressure hot water, but the flow is limited by the boiler's output, and it can drop if a second tap or shower is used at the same time. With an unvented cylinder, a mixer gets strong, balanced pressure on hot and cold and suits large bathrooms and rainfall heads. With a gravity-fed system, where hot water comes from a cylinder fed by a tank in the loft, a mixer on its own can be weak, especially on upper floors close to the tank, and often needs a shower pump. Our guides to mains pressure vs gravity-fed plumbing and which shower pump you need explain the difference.

Flow and the feel of the shower. If you want a drenching rainfall head or body jets, you need a mixer with a good supply behind it; an electric shower cannot heat enough water per minute for that. If you want a reliable, decent shower with no waiting for hot water, an electric shower does the job well. For a family where several people shower one after another, an electric shower will not run out, whereas a small cylinder can.

Running costs. Electricity usually costs more per unit of heat than gas, but an electric shower only heats the water you actually use, with no stored hot water cooling in a cylinder. A mixer fed by a gas combi heats water on demand too. A mixer fed by a cylinder uses water that was heated in advance, and part of that heat is lost from the cylinder and pipes. Which is cheaper in your home depends on your tariff, how long people shower and how your hot water is heated. The bigger saving on either type usually comes from shorter showers and a sensible flow rate.

Installation: electric showers. An electric shower needs only a cold mains feed, which makes it simple to plumb almost anywhere, including a loft conversion or a cloakroom far from the boiler. The electrical side is the bigger job. A modern electric shower needs its own dedicated circuit from the consumer unit, sized for its kilowatt rating, with the right protection and an isolating switch. Fitting a new circuit is notifiable electrical work and must be done by a qualified electrician. Swapping an old electric shower for a new one of a similar rating is simpler, but a higher-rated unit may need the cable upgrading. The plumbing side still needs the mains pressure checked, since electric showers need a minimum pressure to work properly.

Installation: mixer showers. A mixer needs hot and cold pipes to reach the valve, ideally at balanced pressures. A bar mixer on the surface is the simpler option and suits a refit on a budget. A concealed valve looks cleaner but means chasing the wall and tiling over it, so it is best done during a full bathroom renovation. On a gravity-fed system, the pump adds its own position, power supply and noise to plan for. If you are already renovating, our bathroom renovation plumbing guide covers where the shower fits into the sequence.

Chelsea homes: what usually works. Many flats in SW3 and SW10 run on a combi, which pairs well with a thermostatic mixer as long as expectations match the boiler's output. Larger period houses with an unvented cylinder can run bigger mixer showers in more than one bathroom. Older houses still on tanks and a vented cylinder often get the best result from a pumped mixer, or an electric shower in a secondary bathroom. In mansion blocks with communal hot water, it is worth checking the building's supply and the lease before choosing, since some buildings restrict pumps or alterations to the shared system.

Electric showers as a backup. One advantage people only appreciate when the boiler fails is that an electric shower keeps working. In a house with a single mixer shower, adding an electric shower to a second bathroom means nobody goes without a hot shower while a boiler part is on order.

Temperature stability and safety. Both types are available with thermostatic control. A thermostatic mixer compensates when pressure changes elsewhere in the house, which reduces the risk of a sudden burst of hot water. Electric showers have built-in temperature and pressure protection. For older users and young children, look for thermostatic control whichever type you choose. Our guide to thermostatic mixing valves explains how anti-scald protection works.

Common faults on each type. Electric showers tend to fail at the element, the pressure switch or the solenoid valve, and limescale shortens their life in hard water areas like London. Mixers tend to develop problems in the thermostatic cartridge, which can stick with scale and cause the temperature to swing. If your shower suddenly runs cold, our guide on why a shower runs cold helps narrow it down for both types, and our guide to an electric shower not working covers dead units, tripping breakers and water leaking from the base.

Getting it right first time. Emergency Plumber Chelsea checks your water pressure and hot water supply, tells you honestly which type will give you the shower you want, and fits the plumbing side cleanly. Where a new circuit is needed for an electric shower, that part must be carried out by a qualified electrician. There is no call-out fee on jobs over 3 hours. See our shower repairs and installation service or call 020 3002 6667 for SW3, SW10, Knightsbridge, Sloane Square, South Kensington and Fulham.

Quick tips

• Start with your hot water system: combi, unvented cylinder or gravity-fed decides what a mixer can deliver.
• Choose an electric shower for a second bathroom or a room far from the boiler.
• A new electric shower circuit is notifiable electrical work and needs a qualified electrician.
• Pick thermostatic control on either type if children or older people use the shower.
• In hard water, descale the shower head regularly; scale shortens the life of both elements and cartridges.

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